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Meadow battles invaders

FOREST HILLS—The Bussey Brook Meadow section of Arnold Arboretum is yet another battleground in Jamaica Plain’s war against invasive plant species. As with similar control efforts in Franklin and Olmsted parks, volunteers are relied on to reign in such invaders as Japanese knotweed and phragmites (the common reed).

The 24-acre urban wild—which also features wetlands and hills—lies across South Street from the arboretum proper, and was added to its portfolio about a decade ago. Overseen by arboretum staff and nominally owned by the City of Boston, the park is assisted by the private Arboretum Park Conservancy (APC), a non-profit group that advocated for the park’s creation.

APC, with assistance from the New England Wild Flower Society (NEWFS), conducted a botanical inventory of the meadow and recently delivered it to Mayor Thomas Menino—at a City Hall art exhibit featuring illustrations of the meadow’s plants.

“The inventory showed we have lots of invasive species and limited resources,” said APC board member Marjorie Greville. “The invasive problem is so expensive to deal with, and it takes forever.”

There are 33 invasive plant species in the park—about 10 percent of the total number of plant species, according to the inventory.

Greville said APC has adopted a less-than-ideal management plan of containing, rather than eradicating, the invasives. No new plantings of native species are planned, according to Ailene Kane, a NEWFS volunteer coordinator and JP resident who advised APC about invasives.

Invasives are tough plants from other ecosystems that spread elsewhere, usually by humans planting them. The plants find little or no competition in their new home and take over, choking out other plants and impacting the entire ecosystem. Animals, insects, fungi and even microbes can also be invasive species.

APC currently uses young volunteers for the labor-intensive work of cutting back knotweed, one of the meadow’s worst invaders. The plant is highly aggressive, can resprout from the smallest cutting and grows tall and thick.

“We want to keep the invaders from invading,” Greville said, noting that arboretum staff assist the effort by keeping the meadow area regularly mowed, preserving a large section of native grasses.

The wetlands have a population of phragmites, the towering reeds that currently choke the Muddy River from Olmsted Park through the Fenway.

“Phragmites and knotweed are two we would like to get rid of,” Greville said. But eliminating them is very difficult. Both species are being targeted elsewhere with herbicide injected directly into each plant. Greville said that’s not an option for APC.

Another enemy is black swallowwort, an invasive that Greville said should be replaced by native milkweed plants. Monarch butterflies lay their eggs on milkweed so the larvae can feed on them; sometimes they mistake swallowwort for milkweed, and the larvae can’t eat that invasive. The inventory calls swallowwort removal a “high priority.”

Other problem species in the meadow include purple loosestrife, tree of heaven, fig buttercup and glossy and common buckthorn.

As in other local parks, invasive species management for the meadow produces some mixed feelings. “Some of them provide some habitat for birds,” Greville noted. And some species are attractive—often why they were introduced by humans in the first place.

“We have yellow iris throughout the wetlands that the public tends to enjoy [and] doesn’t realize they’re invasives,” Greville said.

APC and NEWFS completed a plant inventory of the meadow in 2005 that includes the invasive species, but it hasn’t had the desired impact. The main goal of the inventory was to encourage local schools to use the meadow as an outdoor classroom, which hasn’t happened, Greville said.

The inventory was illustrated by artist Anne Schmalz, who also illustrated the park’s informational signs that include invasive species descriptions.

Schmalz’s work—including meadow inventory illustrations—is on display this month at City Hall’s Mayor’s Gallery. At a ceremonial exhibit opening on March 8, APC gave a copy of the inventory directly to Menino.

Asked if that was intended as a hint to the Boston Parks and Recreation Department to get involved, Greville laughed and said, “Encouragment, I would say.”

Parks department spokesperson Mary Hines did not have immediate comment about the plant inventory.

For information about volunteering with the APC’s invasive species control effort, call 556-4110. Framingham-based NEWFS offers authoritative information about invasive species management and volunteer opportuntities at www.newfs.org or (508) 877-7630.